Marine

Coral Trout and Moray Eels both love to eat smaller fish. The Coral Trout is best-suited to hunting in the open waters, using its keen eyesight.

The Moray Eel hunts in and around coral reef crevices. It has relatively poor eyesight, but is very agile close to the reef.

The Coral Trout wishes it could get to prey that hide in the reef, and the Moray Eel wishes it could see better.

So They Team Up!

Literally, the Coral Trout chooses a Moray Eel and they go hunting. The Coral Trout indicates with a shake of the head when it has found some lunch. The Moray Eel flushes it out, and then tries to eat it. If it escapes to the open water, the Coral Trout has a go.

Is this the only animal + animal hunting partnership?

Interestingly, the Coral Trout (a type of Red Grouper) will return to team up with the eels that it had the most success worth, according to a recent study published in Current Biology and publicised by New Scientist.

First off, a sponge can somehow fibre-optic cables, and they beat humans by inventing it 500 million years before us!

It’s amazing all around. It lives on the ocean floor, and it grows itself a skeleton made of glass. When people make glass, they do it at 2,000 degrees Celsius, but somehow these organisms synthesize glass fibers at ambient temperatures.

Then, at the sponge’s base, where it is attached to the ocean floor, it has a crown of thin strands that behave like nearly perfect optical fibers, which guide light from one end to the other. We think that we invented optical fibers 60 years ago; nature created optical fibers—from the same material we use—half a billion years earlier.

The second amazing aspect of the sponge is the relationship it has with bioluminescent bacteria and shrimp:

But the sponge lives in darkness. Why would it create such a sophisticated fiber-optical system? It turns out that it lives symbiotically. Bioluminescent bacteria live on the sponge, and their light shines through the fibers. The crown of illuminated fibers acts like a beacon, attracting other life in the darkness. Then a pair of shrimp live inside the sponge—protected by this illuminated glass house, feeding on all the things that are attracted to the light. The waste from the shrimp then helps to feed the sponge. It’s a complete system.

So, somehow, 500 million years ago, a sponge decided to starting making optical fibres, because it knew it would help the shrimp that live inside it get more food, and then poo more to feed it.

While there’s plenty of literature for beginners on existing symbiotic relationships, less discussed is the origin. Humans and gut bacteria are a good example – the bacteria needed to be the sort that wouldn’t kill us, and our stomach needed to be a suitable environment for them to thrive within. Here’s the thoughts of someone:

While I’m not knee deep in literature about the subject, it seems to me to be an evolutionary symbiotic relationship: bacteria we ingested that could survive in our GI tract and didn’t cause us to poo poo ourselves to death and didn’t cause any other negative side-effects that would prevent it from being passed down from mother to child would be readily able to live in a generation-to-generation symbiotic relationship inside our bodies. Of course there are some bacteria like Clostridium difficile that live in us but are kept in check by the immune system, and when the immune system fails or is artificially inhibited, they can grow uncontrolled and cause all sorts of havoc, so not every bacteria inside us is totally harmless.

This symbiotic relationship is famous and is often studied in high schools, because it was made obvious in the movie Finding Nemo. This relationship is known as mutualism, where both species gains benefit from having the other one with it. The protects the clownfish hides within the poisonous arms of the anemone, and also leaves it some morsels of food leftover from its own meals, which the clownfish eats. To earn its keep, the clownfish removes parasites from the sea anemone, scares away predators, and provides nutrients to the anemone via its excrement.

Whale and Barnacle

This would be the other more famous relationship, this one known as commensalism. The whale gains absolutely nothing from barnacle attaching to its body, yet the barnacle is also harmless. It is the same as humans hitch-hiking. The barnacle benefits greatly for it is a filter-feeder, and doesn’t need to spend any energy bringing the food to its stomach.